During the 1930s, the English had set up a unique air-
tracking radar system developed by Sir Robert Watson-Watt along
the east and south coasts. It could detect objects in the sky
from 100 miles away, and relay the data to a defense network.

The German planes were intercepted and 15 bombers were shot
down, with no RAF losses. By the beginning of September, the
Luftwaffe had lost more than 800 aircraft with many more
seriously damaged.

German intelligence never appreciated the importance of the
radar, and Goering’s failure to attack the clearly vulnerable
stations amazed the British command.

I spoke with Paul Kennedy, author of “Engineers of
Victory: The Problem Solvers Who Turned the Tide in the Second
World War,” on the following topics: